This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 0119 Studies with first episode populations offer the unique opportunity to examine the effectiveness and side effects of medications without the confounding effects of prior medication use. In addition, successful treatment of the initial psychotic episode is crucial for minimizing the cascading effects of social and vocational deterioration. Newer second generation antipsychotics with lower risks of weight gain and other metabolic side effects are now available, but little is known about their efficacy for first episode subjects, or their efficacy in comparison to risperidone or olanzapine. A crucial question is how much, if any, tradeoff in effectiveness would result if a low weight-gain second generation antipsychotic were used in place of a more widely used second generation antipsychotic. We propose a 12- week random-assignment, double-blind trial comparing risperidone with aripiprazole, a second-generation antipsychotic with a lower risk of metabolic side effects, as first treatment for subjects with schizophrenia spectrum disorders. In addition to the multi-dimensional assessment of treatment outcomes in our current study, the proposed study will feature a more comprehensive assessment of side effects with a focus upon metabolic and other side effects with important health consequences. To enhance generalizability of the findings, we will recruit subjects from settings serving diverse ethnic groups and use broad inclusion criteria.